EP0286934B1 - Method of reducing lining wear in a ladle containing a melt - Google Patents

Method of reducing lining wear in a ladle containing a melt Download PDF

Info

Publication number
EP0286934B1
EP0286934B1 EP88105362A EP88105362A EP0286934B1 EP 0286934 B1 EP0286934 B1 EP 0286934B1 EP 88105362 A EP88105362 A EP 88105362A EP 88105362 A EP88105362 A EP 88105362A EP 0286934 B1 EP0286934 B1 EP 0286934B1
Authority
EP
European Patent Office
Prior art keywords
melt
slag
stirrer
electromagnetic
ladle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP88105362A
Other languages
German (de)
French (fr)
Other versions
EP0286934A1 (en
Inventor
Hans Ekander
Clas Ericson
Göte Tallbäck
Hernan Tinoco
Staffan Öström
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB AB
Original Assignee
Asea Brown Boveri AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Asea Brown Boveri AB filed Critical Asea Brown Boveri AB
Publication of EP0286934A1 publication Critical patent/EP0286934A1/en
Application granted granted Critical
Publication of EP0286934B1 publication Critical patent/EP0286934B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D27/00—Stirring devices for molten material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/45—Magnetic mixers; Mixers with magnetically driven stirrers
    • B01F33/451—Magnetic mixers; Mixers with magnetically driven stirrers wherein the mixture is directly exposed to an electromagnetic field without use of a stirrer, e.g. for material comprising ferromagnetic particles or for molten metal
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F2101/00—Mixing characterised by the nature of the mixed materials or by the application field
    • B01F2101/45—Mixing in metallurgical processes of ferrous or non-ferrous materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces heated electrically, with or without any other source of heat
    • F27B3/085—Arc furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D1/00—Casings; Linings; Walls; Roofs
    • F27D2001/0046—Means to facilitate repair or replacement or prevent quick wearing
    • F27D2001/0056—Aspects of construction intended to prevent wear
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D2003/0034—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities
    • F27D2003/0039—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities comprising magnetic means

Definitions

  • the invention relates to a method of mixing melt and slag in a ladle containing a melt according to the pre-characterizing part of Claim 1. Such a method is known from the SE-B-447 846.
  • the SE-B-447 846 describes a crucible furnace comprising a crucible with a central direct current arcing electrode and at least one bottom contact placed in the side wall near the bottom of the crucible.
  • the crucible is surrounded by an electric coil powered by direct current.
  • the magnetic field generated by said coils interacts with the current flowing in the melt in such a way that a horizontally rotating movement of the melt is brought about which turns the surface of the melt into a parabolic shape. This phenomenon is used to protect the lining of the crucible from the heat radiating from the electric arc.
  • the invention aims at developing a method of mixing melt and slag in a ladle of the above-mentioned kind which method exhibits improved intensity of mixing steel and slag to increase metallurgical efficiency such as sulphur removal from a steel melt.
  • the stirring which is suitably obtained from a horizontally acting electromagnetic stirrer fed with multi-phase current, is carried out such that the melt and the slag are brought to rotate horizontally by appropriate arranging the stirrer in relation to a ladle filled with steel melt.
  • the slag accumulates in the central area of the surface of the melt below the arcs and will thus easily be melted down.
  • the disturbing device a turbulence is obtained in the melt, which has metallurgical advantages such as direct sulphur removal and increased homogenization.
  • the melt is stirred not only by a horizontally acting electromagnetic stirrer but additionally by a vertically acting stirrer, separated from and suitably diametrically located in relation to the first-mentioned stirrer.
  • the latter stirrer is provides to increase the homogenization of the melt.
  • Figure 1a shows a ladle 1 and an electromagnetic stirrer 2, fed with multi-phase current and located at the side of the ladle 1.
  • Figure 1b shows the same arrangement from above.
  • the stirring can take place in either of the directions indicated by the arrows 3 and 4.
  • the stirring causes rotation of the melt, for example a steel melt, which rotation enforces a parabolic shape on the surface 5 of the melt, the slag 6 accumulating in the centre thereof where it is easily melted down by the arc 7 from the arcing electrode or electrodes 8.
  • substantial protection of the lining of the ladle 1 is obtained.
  • substantial protection is obtained against direct radiation from the arc 7 towards the wall of the ladle 1.
  • the arrangement can be supplemented with a vertical stirrer 9, which stirs in the vertical direction and increases the homogenization of the melt and the homogenization of the temperature in the melt.
  • the slag accumulated at the centre will thus be readily melted down. Refining effects, such as sulphur removal, can be obtained and possibly improved. In this connection also an efficient mixing of steel and slag is obtained.
  • the ladle 1 is provided with a disturbing device as will be described in the following.
  • Figures 2a and 2b show the immersion of a disturbing pole or rod 10 of ceramic, or other refractory material, into the melt. This disturbs the motion of the melt caused by the horizontally acting stirrer 11 and leads to a more efficient mixing of steel and slag, which, among other things, increases the intensity of the sulphur removal.
  • Figure 2b shows the stirring direction and the ceramic pole 10, which is arranged eccentrically in relation to the vertical axis of the ladle and at the interface between steel and slag.
  • Figures 3a and 3b show a device similar to that shown in Figures 2a, 2b, but with the disturbing device in the form of a ceramic stone, such as a brick 12, projecting into the melt, suitably below the surface of the melt at the ladle wall.
  • a ceramic stone such as a brick 12
  • the ceramic stone 12 is to have such dimensions that it projects from the inner wall of the ladle into the melt at or immediately below the surface of the melt (see Figure 3a).
  • FIG. 4a and 4b An alternative embodiment of a disturbing device is shown in Figures 4a and 4b, in which a ceramic wing 12 is immersed into the melt or arranged below the melt surface. Also in this case, intensified mixing of slag and steel melt is obtained.
  • Figure 5 shows an electromagnetic disturbing device, consisting of an iron core 15 surrounded by a coil 14.
  • the iron core 15 projects down towards the melt and magnetically presses down the melt when the coil 14 is supplied with current (see the melt surface 16).
  • Figures 6a and 6b show the parabolic surface 17 caused by the stirrer which is not being shown. It also shows the iron core 15 and the coil 14 the magnetic field of which presses down the melt to an additional extent for the purpose of intensifying the rate of mixing.
  • the electromagnetic disturbing device which locally decelerates the melt may, for example, create a stationary alternating field, a travelling field (suitably with a frequency different from that of the stirrer 2), and/or a continuous field.
  • the position of the disturbing pole is also shown in Figure 6b, which is a view from above on the ladle in Figure 6a.
  • Figures 7a and 7b show an electromagnet 18 with its coil being supplied with direct current and acting at a location in the ladle substantially diametrically opposite to that of the stirrer 2, which acts in the horizontal direction in order to achieve a parabolic melt surface 19.
  • the d.c. supplied magnet 18 decelerates the melt locally, thus causing increased stirring (see also the cross section in Figure 7b).

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

Description

  • The invention relates to a method of mixing melt and slag in a ladle containing a melt according to the pre-characterizing part of Claim 1. Such a method is known from the SE-B-447 846.
  • The SE-B-447 846 describes a crucible furnace comprising a crucible with a central direct current arcing electrode and at least one bottom contact placed in the side wall near the bottom of the crucible. The crucible is surrounded by an electric coil powered by direct current. The magnetic field generated by said coils interacts with the current flowing in the melt in such a way that a horizontally rotating movement of the melt is brought about which turns the surface of the melt into a parabolic shape. This phenomenon is used to protect the lining of the crucible from the heat radiating from the electric arc.
  • One problem in connection with a furnace of the afore-mentioned kind is the mixing of steel melt and slag, for example for sulphur removal. The homogenization of the melt may also present problems.
  • A Method and a device for increasing the efficiency of reactions between slag and melt in a bath of molten metal, for example in connection with sulphur removal from steel melts, is described in the prior, not pre-published EP-A-86117529.7. With this method, stirring of the melt takes place by means of at least one inductive stirrer, the stirring being performed in such a way that the force vector of the stirring is composed of a horizontal and a vertical component.
  • The invention aims at developing a method of mixing melt and slag in a ladle of the above-mentioned kind which method exhibits improved intensity of mixing steel and slag to increase metallurgical efficiency such as sulphur removal from a steel melt.
  • To achieve this aim the invention suggests a method according to the introductory part of Claim 1, which is characterized by the features of the characterizing part of Claim 1.
  • Further developments of the invention are characterized by the features of the additional claims.
  • The stirring, which is suitably obtained from a horizontally acting electromagnetic stirrer fed with multi-phase current, is carried out such that the melt and the slag are brought to rotate horizontally by appropriate arranging the stirrer in relation to a ladle filled with steel melt. This results in great flexibility with respect to the flow pattern. During horizontal rotation of the melt, the slag accumulates in the central area of the surface of the melt below the arcs and will thus easily be melted down. In addition, by the action of the disturbing device a turbulence is obtained in the melt, which has metallurgical advantages such as direct sulphur removal and increased homogenization.
  • By the method according to the invention, contact between slag and lining can be avoided and thus the wear of the lining be reduced. The parabolic surface protects the ladle wall from radiation emanating from the arcs.
  • In one embodiment of the invention, the melt is stirred not only by a horizontally acting electromagnetic stirrer but additionally by a vertically acting stirrer, separated from and suitably diametrically located in relation to the first-mentioned stirrer. The latter stirrer is provides to increase the homogenization of the melt.
  • By increasing the parabola height by increased horizontal rotation, the current as well as electrode consumption can be reduced.
  • The invention will now be described in greater detail with reference to the accompanying drawings showing - by way of example - in
    • Figures 1a and 1b the use of two stirrers,
    • Figures 2a and 2b the use of a ceramic pole as a disturbing device,
    • Figures 3a and 3b the use of a ceramic stone as a disturbing device,
    • Figures 4a and 4b the use of a ceramic wing as a disturbing device,
    • Figure 5 an electromagnetically functioning disturbing pole,
    • Figures 6a and 6b the application of the disturbing pole shown in Figure 5,
    • Figures 7a and 7b a disturbing device in the form of an electromagnet,
    • Figure 8 an arrangement with a horizontal stirrer and an electromagnet.
  • Figure 1a shows a ladle 1 and an electromagnetic stirrer 2, fed with multi-phase current and located at the side of the ladle 1. Figure 1b shows the same arrangement from above. By selecting the direction of the travelling magnetic field, the stirring can take place in either of the directions indicated by the arrows 3 and 4. The stirring causes rotation of the melt, for example a steel melt, which rotation enforces a parabolic shape on the surface 5 of the melt, the slag 6 accumulating in the centre thereof where it is easily melted down by the arc 7 from the arcing electrode or electrodes 8. In this way, substantial protection of the lining of the ladle 1 is obtained. Also, substantial protection is obtained against direct radiation from the arc 7 towards the wall of the ladle 1. Direct contact between slag and lining is also avoided, which considerably increases the life time of the lining. If desired, the arrangement can be supplemented with a vertical stirrer 9, which stirs in the vertical direction and increases the homogenization of the melt and the homogenization of the temperature in the melt. The slag accumulated at the centre will thus be readily melted down. Refining effects, such as sulphur removal, can be obtained and possibly improved. In this connection also an efficient mixing of steel and slag is obtained.
  • The ladle 1, is provided with a disturbing device as will be described in the following.
  • Figures 2a and 2b show the immersion of a disturbing pole or rod 10 of ceramic, or other refractory material, into the melt. This disturbs the motion of the melt caused by the horizontally acting stirrer 11 and leads to a more efficient mixing of steel and slag, which, among other things, increases the intensity of the sulphur removal. Figure 2b shows the stirring direction and the ceramic pole 10, which is arranged eccentrically in relation to the vertical axis of the ladle and at the interface between steel and slag.
  • Figures 3a and 3b show a device similar to that shown in Figures 2a, 2b, but with the disturbing device in the form of a ceramic stone, such as a brick 12, projecting into the melt, suitably below the surface of the melt at the ladle wall. In the same way as in the case of the above-described pole 10, a disturbance of the stirring and hence an intensified mixing of slag and steel are obtained. The ceramic stone 12 is to have such dimensions that it projects from the inner wall of the ladle into the melt at or immediately below the surface of the melt (see Figure 3a).
  • An alternative embodiment of a disturbing device is shown in Figures 4a and 4b, in which a ceramic wing 12 is immersed into the melt or arranged below the melt surface. Also in this case, intensified mixing of slag and steel melt is obtained.
  • Figure 5 shows an electromagnetic disturbing device, consisting of an iron core 15 surrounded by a coil 14. The iron core 15 projects down towards the melt and magnetically presses down the melt when the coil 14 is supplied with current (see the melt surface 16). The application is also clear from Figures 6a and 6b, which show the parabolic surface 17 caused by the stirrer which is not being shown. It also shows the iron core 15 and the coil 14 the magnetic field of which presses down the melt to an additional extent for the purpose of intensifying the rate of mixing. The electromagnetic disturbing device which locally decelerates the melt may, for example, create a stationary alternating field, a travelling field (suitably with a frequency different from that of the stirrer 2), and/or a continuous field. The position of the disturbing pole is also shown in Figure 6b, which is a view from above on the ladle in Figure 6a.
  • Figures 7a and 7b show an electromagnet 18 with its coil being supplied with direct current and acting at a location in the ladle substantially diametrically opposite to that of the stirrer 2, which acts in the horizontal direction in order to achieve a parabolic melt surface 19. The d.c. supplied magnet 18 decelerates the melt locally, thus causing increased stirring (see also the cross section in Figure 7b).
  • In prior art ladles with normal stirring, the removal of sulphur from steel proceeds relatively slowly. With the method according to the invention, among other things according to Figure 8, the rate of mixing of slag and melt, and therefore the sulphur removal, can be improved. A horizontally acting stirrer 21, acting in the circumferential direction, is placed at the ladle 20. Diametrically opposite thereto, or somewhat angularly displaced in relation thereto, an electromagnetic coil 22 is arranged which generates a magnetic field at the surface of the melt, which acts as an electromagnetic brake. At the location of the coil 22, the surface dividing the slag and the melt is disturbed, thus obtaining a vigorous mixing. Figure 8 clearly shows the location of the coil 22 in relation to the slag 23, and the mixing starts at 24.

Claims (10)

  1. Method of mixing melt and slag in a ladle containing a melt, preferably a steel melt, which is heated by at least one electric arc (7) and rotated, with the help of current-supplied electromagnetic coils (2), in a horizontal direction such that a parabolic surface forms on the melt protecting the ladle lining against radiation of the arc, characterized in that said coils form an electromagnetic stirrer (2) generating a horizontally travelling magnetic field the force of which is chosen such that the slag (6) present in the melt accumulates in the central area, thus protecting the ladle lining also against the attack of the slag, that the arc or arcs (7), in addition to heating the charge, also melts/melt the slag (6), and that a disturbing device (10,12) is provided, adapted to bring about an efficient mixing of melt and slag.
  2. Method according to claim 1, characterized in that said disturbing device comprises a pole or rod (10) of ceramic or other refractory material immersing into the melt, preferably into the interface between melt and slag.
  3. Method according to claim 1, characterized in that said disturbing device comprises a ceramic stone, for example a brick (12), projecting into the melt, suitably below the surface of the melt at the ladle wall.
  4. Method according to claim 1, characterized in that said disturbing device comprises a ceramic wing (13) immersing into or arranged below the bath surface, preferably into/in the interface between melt and slag.
  5. Method according to claim 1, characterized in that said disturbing device comprises an electromagnetic brake.
  6. Method according to Claim 1, characterized in that said disturbing device comprises an electromagnetic disturbing pole (14,15) which may be lowered towards the surface of the melt, said disturbing pole magnetically pressing down the melt surface.
  7. Method according to Claim 5, characterized in that a magnet (18), supplied with direct current, or other electromagnetic means is/are applied at the melt surface of the ladle, said magnet or other electromagnetic means decelerating the melt by producing a continuous magnetic field, a stationary alternating magnetic field or a travelling magnetic field, separated from that of the ordinary stirrer (2).
  8. Method according to any of the preceding claims, characterized in that the melt is stirred by a horizontally acting, electromagnetic stirrer (2) and by a vertically acting stirrer (9), separated from and suitably diametrically located in relation to the first-mentioned stirrer.
  9. Method according to Claim 5, characterized in that the stirring obtained by the horizontally acting, electromagnetic stirrer (2) is disturbed by an additional magnetic field generated by a coil (22), substantially diametrically located in relation to the stirrer (2), said coil (22) being supplied with direct current or single-phase alternating current such as to act as an electromagnetic brake.
  10. Method according to any of the preceding claims, characterized in that the parabola height is increased by increased horizontal rotation, whereby the current as well as the electrode consumption can be reduced.
EP88105362A 1987-04-13 1988-04-02 Method of reducing lining wear in a ladle containing a melt Expired - Lifetime EP0286934B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8701525 1987-04-13
SE8701525A SE460621B (en) 1987-04-13 1987-04-13 SET TO REDUCE FEED WEAR DURING LIGHT BAG HEATING OF STEEL MELT

Publications (2)

Publication Number Publication Date
EP0286934A1 EP0286934A1 (en) 1988-10-19
EP0286934B1 true EP0286934B1 (en) 1993-04-07

Family

ID=20368177

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88105362A Expired - Lifetime EP0286934B1 (en) 1987-04-13 1988-04-02 Method of reducing lining wear in a ladle containing a melt

Country Status (5)

Country Link
US (1) US4820342A (en)
EP (1) EP0286934B1 (en)
JP (1) JPS63263383A (en)
DE (1) DE3879994T2 (en)
SE (1) SE460621B (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE464263B (en) * 1988-09-21 1991-03-25 Asea Brown Boveri METHOD AND APPARATUS FOR MOVING A METAL MELT
SE504400C2 (en) * 1995-04-25 1997-02-03 Asea Brown Boveri Oven plant for melting metal and / or hot holding of molten metal
RU2132028C1 (en) * 1998-03-30 1999-06-20 Красноярский государственный технический университет Method for electromagnetically agitating electrically conductive melt
FR2840821B1 (en) * 2002-06-13 2005-03-04 Commissariat Energie Atomique ELECTROMAGNETIC DEVICE FOR FUSION AND INTERFACIAL AGITATION OF DIPHASIC SYSTEMS, IN PARTICULAR FOR THE ACCELERATION OF METALLURGIC OR PYROCHEMICAL PROCESSES
CN106563777A (en) * 2015-10-08 2017-04-19 富准精密工业(深圳)有限公司 Preparation method and device for semi-solid metal slurry
CN107042299A (en) * 2017-06-16 2017-08-15 武汉科技大学 The control device and method of a kind of refining ladle slag emulsification

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR764178A (en) * 1933-02-06 1934-05-16 Applic Electro Thermiques Soc Improvement in induction furnaces
US2139853A (en) * 1933-07-08 1938-12-13 Heraeus Vacuumschmelze Ag Method of making steel
DE726975C (en) * 1933-12-04 1942-10-23 Stalturbine G M B H Coreless induction furnace
US3246373A (en) * 1962-06-22 1966-04-19 United States Steel Corp Magnetic stirring device and method
US3160497A (en) * 1962-11-15 1964-12-08 Loung Pai Yen Method of melting refractory metals using a double heating process
SE447846B (en) * 1982-09-09 1986-12-15 Asea Ab DINNER WITH DIRECT HEATING
JPS6096735A (en) * 1983-10-31 1985-05-30 Kawasaki Steel Corp Arc heating method of molten metal
SE452991B (en) * 1985-12-20 1988-01-04 Asea Ab SET AND DEVICE FOR EFFICIENTLY EFFECTIVELY BATTERY / BATHROOM REACTIONS BY INDUCTIVE MIRRORING

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Patent abstract of Japan Vol.9, no 237 c-305, abstract of Japan 60-96735, publ 30 May 1985. *

Also Published As

Publication number Publication date
SE8701525D0 (en) 1987-04-13
DE3879994D1 (en) 1993-05-13
SE8701525L (en) 1988-10-14
EP0286934A1 (en) 1988-10-19
DE3879994T2 (en) 1993-09-16
US4820342A (en) 1989-04-11
JPS63263383A (en) 1988-10-31
SE460621B (en) 1989-10-30

Similar Documents

Publication Publication Date Title
CA1300898C (en) Melting furnace and method for melting metal
US5074532A (en) Electro-magnetic nozzle device for controlling a stream of liquid metal tapped from a crucible
US5563904A (en) Process for melting an electroconductive material in a cold crucible induction melting furnace and melting furnace for carrying out the process
EP0653967B1 (en) A method and device for stirring a molten metal
US5479438A (en) Apparatus for fusing a solid layer of electrically conductive material
US6550526B1 (en) Method and device for producing cast parts consisting of aluminium and magnesium alloys
JPH06200334A (en) Equipment for the production of high-purity metals and alloys
JP2004108666A (en) Crucible induction furnace
US2686823A (en) Rotary electric field fluid stirring apparatus
US4139722A (en) Electric induction heating furnace
US4769066A (en) Method for removing inclusions from a bath of molten metal and a device for carrying out this method
EP0853131B1 (en) Process and plant for induction melting and purification of aluminium, coper, brass, lead and bronze alloys
KR100261516B1 (en) Strap Melting Process and Apparatus
EP0286934A1 (en) Method of reducing lining wear in a ladle containing a melt
US2319402A (en) Desulphurizing apparatus
KR100556715B1 (en) Induction furnaces and methods for melting fine metal particles and / or metal containing particles
JPS5966684A (en) Ladle furnace
EP0228024B1 (en) Method of rendering slag-bath reactions more efficient and arrangement for carrying out the method
US3579324A (en) Method for induction melting of fine particles
KR20200139276A (en) Furnace assembly for a metal-making process
US4735256A (en) Heating apparatus for intermediate ladles or tundishes
KR19980032784A (en) Method and apparatus for electronically stirring liquid metal in electric arc furnace.
US5275229A (en) Magnetic suspension melting apparatus
JPH04227466A (en) Dc arc furnace
RU2104607C1 (en) Method for electromagnetic control of rotary motion of electricity conducting body

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19890316

17Q First examination report despatched

Effective date: 19900917

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

REF Corresponds to:

Ref document number: 3879994

Country of ref document: DE

Date of ref document: 19930513

ITF It: translation for a ep patent filed
ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19990401

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19990409

Year of fee payment: 12

Ref country code: DE

Payment date: 19990409

Year of fee payment: 12

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20000402

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20000402

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20001229

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010201

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050402